July-August, Volume 87, No. 4

Figure 4. Ocean-bottom sediments are collected using a 10-meter-long piston core barrel. Analysis of the chemical makeup of the shells of foraminifera, the mineralogy of the sediments, and the types of organic compounds made and deposited by phytoplankton indicate what the seawater temperature, salinity and source areas were when the sediments were deposited. (Photograph courtesy of Anne Jennings.)